Remove "this==NULL" and adjust corresponding callers

core/src/fpdfdoc/doc_ap.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../../include/fpdfdoc/fpdf_doc.h"
 #include "../../include/fpdfdoc/fpdf_vt.h"
 #include "pdf_vt.h"
 #include "../../include/fpdfdoc/fpdf_ap.h"
 FX_BOOL FPDF_GenerateAP(CPDF_Document* pDoc, CPDF_Dictionary* pAnnotDict)
 {
-    if (pAnnotDict->GetConstString("Subtype") != FX_BSTRC("Widget")) {
+    if (!pAnnotDict || pAnnotDict->GetConstString("Subtype") != FX_BSTRC("Widget")) {
         return FALSE;
     }
     CFX_ByteString field_type = FPDF_GetFieldAttr(pAnnotDict, "FT")->GetString();
-    FX_DWORD flags = FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger();
+    FX_DWORD flags = FPDF_GetFieldAttr(pAnnotDict, "Ff")? FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger() : 0;
     if (field_type == "Tx") {
         return CPVT_GenerateAP::GenerateTextFieldAP(pDoc, pAnnotDict);
     } else if (field_type == "Ch") {
         if (flags & (1 << 17)) {
             return CPVT_GenerateAP::GenerateComboBoxAP(pDoc, pAnnotDict);
         } else {
             return CPVT_GenerateAP::GenerateListBoxAP(pDoc, pAnnotDict);
         }
     } else if (field_type == "Btn") {
         if (!(flags & (1 << 16))) {
@@ skipping 218 matching lines @@
 }
 static FX_BOOL GenerateWidgetAP(CPDF_Document* pDoc, CPDF_Dictionary* pAnnotDict, const FX_INT32 & nWidgetType)
 {
     CPDF_Dictionary* pFormDict = NULL;
     if (CPDF_Dictionary * pRootDict = pDoc->GetRoot()) {
         pFormDict = pRootDict->GetDict("AcroForm");
     }
     if (!pFormDict) {
         return FALSE;
     }
-    CFX_ByteString DA = FPDF_GetFieldAttr(pAnnotDict, "DA")->GetString();
+    CFX_ByteString DA = FPDF_GetFieldAttr(pAnnotDict, "DA") ? FPDF_GetFieldAttr(pAnnotDict, "DA")->GetString() : CFX_ByteString();
     if (DA.IsEmpty()) {
         DA = pFormDict->GetString("DA");
     }
     if (DA.IsEmpty()) {
         return FALSE;
     }
     CPDF_SimpleParser syntax(DA);
     syntax.FindTagParam("Tf", 2);
     CFX_ByteString sFontName = syntax.GetWord();
     sFontName = PDF_NameDecode(sFontName);
     if (sFontName.IsEmpty()) {
         return FALSE;
     }
     FX_FLOAT fFontSize = FX_atof(syntax.GetWord());
     CPVT_Color crText = ParseColor(DA);
     FX_BOOL bUseFormRes = FALSE;
     CPDF_Dictionary * pFontDict = NULL;
     CPDF_Dictionary* pDRDict = pAnnotDict->GetDict(FX_BSTRC("DR"));
     if (pDRDict == NULL) {
         pDRDict = pFormDict->GetDict(FX_BSTRC("DR"));
         bUseFormRes = TRUE;
     }
     CPDF_Dictionary * pDRFontDict = NULL;
-    if ((pDRFontDict = pDRDict->GetDict("Font"))) {
+    if (pDRDict && (pDRFontDict = pDRDict->GetDict("Font"))) {
         pFontDict = pDRFontDict->GetDict(sFontName.Mid(1));
         if (!pFontDict && !bUseFormRes) {
             pDRDict = pFormDict->GetDict(FX_BSTRC("DR"));
             pDRFontDict = pDRDict->GetDict("Font");
             if (pDRFontDict) {
                 pFontDict = pDRFontDict->GetDict(sFontName.Mid(1));
             }
         }
     }
     if (!pDRFontDict) {
@@ skipping 132 matching lines @@
             if (!pStreamResFontList->KeyExist(sFontName)) {
                 pStreamResFontList->SetAtReference(sFontName, pDoc, pFontDict);
             }
         } else {
             pStreamDict->SetAt("Resources", pFormDict->GetDict("DR")->Clone());
             pStreamResList = pStreamDict->GetDict("Resources");
         }
     }
     switch (nWidgetType) {
         case 0: {
-                CFX_WideString swValue = FPDF_GetFieldAttr(pAnnotDict, "V")->GetUnicodeText();
-                FX_INT32 nAlign = FPDF_GetFieldAttr(pAnnotDict, "Q")->GetInteger();
-                FX_DWORD dwFlags = FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger();
-                FX_DWORD dwMaxLen = FPDF_GetFieldAttr(pAnnotDict, "MaxLen")->GetInteger();
-                CPVT_FontMap map(pDoc, pStreamDict->GetDict("Resources"), pDefFont, sFontName.Right(sFontName.GetLength() - 1));
+                CFX_WideString swValue = FPDF_GetFieldAttr(pAnnotDict, "V")? FPDF_GetFieldAttr(pAnnotDict, "V")->GetUnicodeText() : CFX_WideString();
+                FX_INT32 nAlign = FPDF_GetFieldAttr(pAnnotDict, "Q")? FPDF_GetFieldAttr(pAnnotDict, "Q")->GetInteger() : 0;
+                FX_DWORD dwFlags = FPDF_GetFieldAttr(pAnnotDict, "Ff")? FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger() : 0;
+                FX_DWORD dwMaxLen = FPDF_GetFieldAttr(pAnnotDict, "MaxLen") ? FPDF_GetFieldAttr(pAnnotDict, "MaxLen")->GetInteger() : 0;
+                CPVT_FontMap map(pDoc, pStreamDict ? pStreamDict->GetDict("Resources") : NULL , pDefFont, sFontName.Right(sFontName.GetLength() - 1));
                 CPVT_Provider prd(&map);
                 CPDF_VariableText vt;
                 vt.SetProvider(&prd);
                 vt.SetPlateRect(rcBody);
                 vt.SetAlignment(nAlign);
                 if (IsFloatZero(fFontSize)) {
                     vt.SetAutoFontSize(TRUE);
                 } else {
                     vt.SetFontSize(fFontSize);
                 }
@@ skipping 27 matching lines @@
                     if (rcContent.Width() > rcBody.Width() ||
                             rcContent.Height() > rcBody.Height()) {
                         sAppStream << rcBody.left << " " << rcBody.bottom << " "
                                    << rcBody.Width() << " " << rcBody.Height() << " re\nW\nn\n";
                     }
                     sAppStream << "BT\n" << CPVT_GenerateAP::GenerateColorAP(crText, TRUE) << sBody << "ET\n" << "Q\nEMC\n";
                 }
             }
             break;
         case 1: {
-                CFX_WideString swValue = FPDF_GetFieldAttr(pAnnotDict, "V")->GetUnicodeText();
-                CPVT_FontMap map(pDoc, pStreamDict->GetDict("Resources"), pDefFont, sFontName.Right(sFontName.GetLength() - 1));
+                CFX_WideString swValue = FPDF_GetFieldAttr(pAnnotDict, "V") ? FPDF_GetFieldAttr(pAnnotDict, "V")->GetUnicodeText() : CFX_WideString();
+                CPVT_FontMap map(pDoc, pStreamDict ? pStreamDict->GetDict("Resources"):NULL, pDefFont, sFontName.Right(sFontName.GetLength() - 1));
                 CPVT_Provider prd(&map);
                 CPDF_VariableText vt;
                 vt.SetProvider(&prd);
                 CPDF_Rect rcButton = rcBody;
                 rcButton.left = rcButton.right - 13;
                 rcButton.Normalize();
                 CPDF_Rect rcEdit = rcBody;
                 rcEdit.right = rcButton.left;
                 rcEdit.Normalize();
                 vt.SetPlateRect(rcEdit);
@@ skipping 30 matching lines @@
                         sAppStream << ptCenter.x - 3 << " " << ptCenter.y + 1.5f << " m\n";
                         sAppStream << ptCenter.x + 3 << " " << ptCenter.y + 1.5f << " l\n";
                         sAppStream << ptCenter.x << " " << ptCenter.y - 1.5f << " l\n";
                         sAppStream << ptCenter.x - 3 << " " << ptCenter.y + 1.5f << " l f\n";
                         sAppStream << sButton << "Q\n";
                     }
                 }
             }
             break;
         case 2: {
-                CPVT_FontMap map(pDoc, pStreamDict->GetDict("Resources"), pDefFont, sFontName.Right(sFontName.GetLength() - 1));
+                CPVT_FontMap map(pDoc, pStreamDict ? pStreamDict->GetDict("Resources"):NULL, pDefFont, sFontName.Right(sFontName.GetLength() - 1));
                 CPVT_Provider prd(&map);
-                CPDF_Array * pOpts = FPDF_GetFieldAttr(pAnnotDict, "Opt")->GetArray();
-                CPDF_Array * pSels = FPDF_GetFieldAttr(pAnnotDict, "I")->GetArray();
-                FX_INT32 nTop = FPDF_GetFieldAttr(pAnnotDict, "TI")->GetInteger();
+                CPDF_Array * pOpts = FPDF_GetFieldAttr(pAnnotDict, "Opt") ? FPDF_GetFieldAttr(pAnnotDict, "Opt")->GetArray() : NULL;
+                CPDF_Array * pSels = FPDF_GetFieldAttr(pAnnotDict, "I") ? FPDF_GetFieldAttr(pAnnotDict, "I")->GetArray() : NULL;
+                FX_INT32 nTop = FPDF_GetFieldAttr(pAnnotDict, "TI") ? FPDF_GetFieldAttr(pAnnotDict, "TI")->GetInteger() : 0;
                 CFX_ByteTextBuf sBody;
                 if (pOpts) {
                     FX_FLOAT fy = rcBody.top;
                     for (FX_INT32 i = nTop, sz = pOpts->GetCount(); i < sz; i++) {
                         if (IsFloatSmaller(fy, rcBody.bottom)) {
                             break;
                         }
                         if (CPDF_Object* pOpt = pOpts->GetElementValue(i)) {
                             CFX_WideString swItem;
                             if (pOpt->GetType() == PDFOBJ_STRING) {
@@ skipping 247 matching lines @@
         case CT_GRAY:
             sColorStream << color.fColor1 << " " << (bFillOrStroke ? "g" : "G") << "\n";
             break;
         case CT_CMYK:
             sColorStream << color.fColor1 << " " << color.fColor2 << " " << color.fColor3 << " " << color.fColor4 << " "
                          << (bFillOrStroke ? "k" : "K") << "\n";
             break;
     }
     return sColorStream.GetByteString();
 }